Today, various kinds of electronic devices have capabilities of encoding and transferring multimedia content or decoding and reproducing it. Encoded content is transferred on a multimedia network, and is reproduced by a device that receives the content. Multimedia networks were formed mostly using wired communication technologies such as High-Definition Multimedia Interface (HDMI) in the past. However, as a result of the rapid development of wireless communication technologies seen in recent years, wireless communication networks, for example, wireless local area networks (LANs), have been utilized for transfer of multimedia content.
A device that encodes and delivers content as necessary is generally called a source device. On the other hand, a device that receives content from a source device and reproduces it is called a sink device. In order for a sink device to successfully reproduce content, it is important for a source device to deliver content encoded in a form that meets a condition such as a capability or a communication environment of the sink device to a network. Thus, Patent Literature 1 proposes a technique of controlling an encoding condition when a content server that corresponds to a source device encodes content in accordance with a capability of a terminal that corresponds to a sink device.
Non-Patent Literature 1 is the Wi-Fi Display Technical Specification stipulated by the Wi-Fi Alliance. Wi-Fi Display is also called Wi-Fi CERTIFIED Miracast (a registered trademark). Wi-Fi Display employs Wi-Fi Direct for forming a wireless communication network between wireless LAN devices without passing through an access point as an underlying technology, and defines protocols for transferring high-definition video content from a source device to a sink device. Messaging between devices defined in Non-Patent Literature 1 is based on Real Time Streaming Protocol (RTSP). For example, a source device can inquire about a capability of a sink device using an M3 message of the RTSP and set an operation of the sink device using an M4 message of the RTSP.